U.S. patent application number 13/865287 was filed with the patent office on 2014-05-29 for transparent electrochromic polyimide, method for manufacturing the same, and electrochromic device utilizing the same.
This patent application is currently assigned to INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE. The applicant listed for this patent is INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE. Invention is credited to Yu-Ruei KUNG, Chyi-Ming LEU.
Application Number | 20140146380 13/865287 |
Document ID | / |
Family ID | 50773054 |
Filed Date | 2014-05-29 |
United States Patent
Application |
20140146380 |
Kind Code |
A1 |
KUNG; Yu-Ruei ; et
al. |
May 29, 2014 |
TRANSPARENT ELECTROCHROMIC POLYIMIDE, METHOD FOR MANUFACTURING THE
SAME, AND ELECTROCHROMIC DEVICE UTILIZING THE SAME
Abstract
Disclosed is a transparent electrochromic polyimide, polymerized
of a diamine and a cycloaliphatic dianhydride. The diamine includes
a diamino triphenylamine having the formula: ##STR00001## wherein
R.sup.1 consists of hydrogen, halogen, C.sub.1-6 alkyl group,
C.sub.1-6 alkoxy group, or ##STR00002## and R.sup.2 consists of
hydrogen, halogen, C.sub.1-6 alkyl group, or C.sub.1-6 alkoxy
group. The cycloaliphatic dianhydride includes ##STR00003##
Inventors: |
KUNG; Yu-Ruei; (New Taipei
City, TW) ; LEU; Chyi-Ming; (Jhudong Township,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE |
Chutung |
|
TW |
|
|
Assignee: |
INDUSTRIAL TECHNOLOGY RESEARCH
INSTITUTE
Chutung
TW
|
Family ID: |
50773054 |
Appl. No.: |
13/865287 |
Filed: |
April 18, 2013 |
Current U.S.
Class: |
359/265 ;
528/353 |
Current CPC
Class: |
C09K 9/00 20130101; B32B
17/10513 20130101; G02F 1/15165 20190101; C09K 9/02 20130101; H01L
51/0035 20130101 |
Class at
Publication: |
359/265 ;
528/353 |
International
Class: |
H01L 51/00 20060101
H01L051/00; G02F 1/15 20060101 G02F001/15 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 27, 2012 |
TW |
101144265 |
Claims
1. A transparent electrochromic polyimide, polymerized of a diamine
and a cycloaliphatic dianhydride, wherein the diamine comprises a
diamino triphenylamine having the formula: ##STR00021## wherein
R.sup.1 consists of hydrogen, halogen, C.sub.1-6 alkyl group,
C.sub.1-6 alkoxy group, or ##STR00022## and R.sup.2 consists of
hydrogen, halogen, C.sub.1-6 alkyl group, or C.sub.1-6 alkoxy
group; and the cycloaliphatic dianhydride comprises
##STR00023##
2. The transparent electrochromic polyimide as claimed in claim 1,
wherein the diamine further comprises an ether amine, and the ether
diamine comprises ##STR00024##
3. The transparent electrochromic polyimide as claimed in claim 2,
wherein the diamino triphenylamine and the ether diamine have a
molar ratio of greater than or equal to 20:80 and less than
100:0.
4. An electrochromic device, comprising: a first transparent
conductive layer; an electrolyte layer disposed on the first
conductive layer; a layer of the transparent electrochromic
polyimide as claimed in claim 1 disposed on the electrolyte layer;
and a second transparent conductive layer on the layer of the
transparent electrochromic polyimide.
5. A method of forming a transparent electrochromic polyimide,
comprising: mixing a diamine, a cycloaliphatic dianhydride, a
catalyst, and an organic solvent to form a mixture; heating the
mixture to form a transparent electrochromic polyimide by reacting
the diamine and the cycloaliphatic dianhydride in a one-step
reaction; wherein the diamine comprises a diamino triphenylamine
having the formula: ##STR00025## wherein R.sup.1 consists of
hydrogen, halogen, C.sub.1-6 alkyl group, C.sub.1-6 alkoxy group,
or ##STR00026## and R.sup.2 consists of hydrogen, halogen,
C.sub.1-6 alkyl group, or C.sub.1-6 alkoxy group; and the
cycloaliphatic dianhydride comprises ##STR00027##
6. The method as claimed in claim 5, wherein the diamine further
comprises an ether amine, and the ether diamine comprises
##STR00028##
7. The method as claimed in claim 6, wherein the diamino
triphenylamine and the ether diamine have a molar ratio of greater
than or equal to 20:80 and less than 100:0.
8. The method as claimed in claim 5, wherein the catalyst comprises
triethylamine, tripropylamine, tributylamine, pyridine,
2-methylpyridine, 3-methylpyridine, 4-methylpyridine,
2,4-dimethylpyridine, 2-ethylpyridine, 3-ethylpyridine,
4-ethylpyridine, quinoline, iso-quinoline, 2-methylquinoline, or
combinations thereof.
9. The method as claimed in claim 5, wherein the organic solvent
has a boiling point of 150.degree. C. to 220.degree. C.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is based on, and claims priority
from, Taiwan Application Serial Number 101144265, filed on Nov. 27,
2012, the disclosure of which is hereby incorporated by reference
herein in its entirety
TECHNICAL FIELD
[0002] The technical field relates to a transparent polyimide, and
in particular to its application of an electrochromic device.
BACKGROUND
[0003] Electrochromic devices are attractive in green energy
industries due to their low driving voltage and bistable
properties. Major electrochromic materials are inorganic oxide for
longer lifetime and endurance, however, films thereof are prepared
by expensive processes and equipment such as vacuum deposition,
spray pyrolysis, or sputtering. Even ignoring the cost of
processing, the inorganic oxide still has shortcomings such as slow
electrochromic rate, less color variation, and the likes. Most
electrochromic organic materials are conjugated polymer with more
color variation and fast electrochromic rates. However, the
electrochromic conjugated polymer has shortcomings such as
expensive monomers, a complicated synthesis, and formation by
electro-polymerization. Therefore, the conjugated polymer with a
low molecular weight has a size limited by the electrode size of
the electro-polymerization. In other words, it is difficult to form
the organic electrochromic material with a large area. On the other
hand, the electrochromic conjugated polymer has an appearance of
deep color due to its conjugated length. Although the deep color
can be lightened by applying a voltage, the conjugated polymer
cannot be fully transparent. In other words, the conjugated polymer
must be electrified to affect a transparent state, thereby leading
to the problem of high energy consumption.
[0004] Accordingly, a novel electrochromic organic material to meet
the requirements of transparency, film firming ability, and
electrochromicity is called-for.
SUMMARY
[0005] One embodiment of the disclosure provides a transparent
electrochromic polyimide, polymerized of a diamine and a
cycloaliphatic dianhydride, wherein the diamine comprises a diamino
triphenylamine having the formula:
##STR00004##
wherein R.sup.1 consists of hydrogen, halogen, C.sub.1-6 alkyl
group, C.sub.1-6 alkoxy group, or
##STR00005##
and R.sup.2 consists of hydrogen, halogen, C.sub.1-6 alkyl group,
or C.sub.1-6 alkoxy group; and the cycloaliphatic dianhydride
comprises
##STR00006##
[0006] One embodiment of the disclosure provides an electrochromic
device, comprising: a first transparent conductive layer; an
electrolyte layer disposed on the first conductive layer; a layer
of the transparent electrochromic polyimide as claimed in claim 1
disposed on the electrolyte layer; and a second transparent
conductive layer on the layer of the transparent electrochromic
polyimide.
[0007] One embodiment of the disclosure provides a method of
forming a transparent electrochromic polyimide, comprising: mixing
a diamine, a cycloaliphatic dianhydride, a catalyst, and an organic
solvent to form a mixture; heating the mixture to form a
transparent electrochromic polyimide by reacting the diamine and
the cycloaliphatic dianhydride in a one-step reaction; wherein the
diamine comprises a diamino triphenylamine having the formula:
##STR00007##
wherein R.sup.1 consists of hydrogen, halogen, C.sub.1-6 alkyl
group, C.sub.1-6 alkoxy group, or
##STR00008##
and R.sup.2 consists of hydrogen, halogen, C.sub.1-6 alkyl group,
or C.sub.1-6 alkoxy group; and the cycloaliphatic dianhydride
comprises
##STR00009##
[0008] A detailed description is given in the following embodiments
with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The disclosure can be more fully understood by reading the
subsequent detailed description and examples with references made
to the accompanying drawings, wherein:
[0010] FIG. 1 shows an electrochromic device in one embodiment of
the disclosure.
DETAILED DESCRIPTION
[0011] In the following detailed description, for purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of the disclosed embodiments. It
will be apparent, however, that one or more embodiments may be
practiced without these specific details. In other instances,
well-known structures and devices are shown schematically in order
to simplify the drawing.
[0012] One embodiment of the disclosure provides a transparent
electrochromic polyimide polymerized of a diamine and a
cycloaliphatic dianhydride by a one-step reaction. The diamine
includes a diamino triphenylamine as shown in Formula 1.
##STR00010##
[0013] In Formula 1, R.sup.1 consists of hydrogen, halogen,
C.sub.1-6 alkyl group, C.sub.1-6 alkoxy group, or diphenylamino
group as shown in Formula 2.
##STR00011##
[0014] In Formula 2, R.sup.2 consists of hydrogen, halogen,
C.sub.1-6 alkyl group, or C.sub.1-6 alkoxy group.
[0015] The cycloaliphatic dianhydride can be dianhydrides as shown
in Formulae 3, 4, 5, 6, 7, or other suitable cycloaliphatic
dianhydrides.
##STR00012##
[0016] In another embodiment of the disclosure, the diamine further
includes an ether diamine, and the diamino triphenylamine and the
ether diamine have a molar ratio of greater than or equal to 20:80
and less than 100:0. If the diamine contains an overly low amount
of the diamino triphenylamine, the polyimide will not be obviously
electrochromic due to an overly low optical transmittance change
during the electrification of the polyimide. The ether diamine can
be a para-substituted diamine as shown in Formula 8-1, an
meta-substituted diamine as shown in Formula 8-2, a diamine as
shown in Formula 9 (R.sup.3 is phenylene, biphenylene,
2,2-diphenylpropylene, 2,2-hexafluorodiphenylpropylene,
2,2-diphenyldiisopropylphenylene, or 2,2-diphenylsulfone), or
another suitable ether diamine. It should be understood that the
polyimide polymerized from the diamine further containing the ether
diamine can be a random copolymer, a block copolymer, or an
alternative copolymer. In one embodiment, the polyimide polymerized
from the diamine further containing the ether diamine is a random
copolymer.
##STR00013##
[0017] In one embodiment, the diamine, the cycloaliphatic
dianhydride, a catalyst, and an organic solvent are evenly mixed to
form a mixture. The mixture is heated, such that the diamine and
the cycloaliphatic dianhydride are further reacted to form the
transparent electrochromic polyimide. In one embodiment, the
transparent electrochromic polyimide has a weight average molecular
weight of 1,000 to 300,000. Alternatively, the transparent
electrochromic polyimide has a weight average molecular weight of
120,000 to 150,000. A transparent electrochromic polyimide with an
overly high weight average molecular weight has an insufficient
solubility. A transparent electrochromic polyimide with an overly
low weight average molecular weight has an insufficient
film-forming ability.
[0018] The catalyst of the polymerization can be triethylamine,
tripropylamine, tributylamine, pyridine, 2-methylpyridine,
3-methylpyridine, 4-methylpyridine, 2,4-dimethylpyridine,
2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, quinoline,
iso-quinoline, 2-methylquinoline, or combinations thereof. In one
embodiment, the organic solvent has a boiling point of 150.degree.
C. to 220.degree. C. An organic solvent with an overly high boiling
temperature will be difficult to remove during the film-forming
process. An organic solvent with an overly low boiling temperature
cannot achieve the desired polymerization temperature. For example,
the suitable organic solvent can be N-methyl-2-pyrrolidone (NMP) or
m-cresol.
[0019] The transparent electrochromic polyimide will be transferred
from being colorless to having a specific color (e.g. deep blue)
after being electrified with a suitable voltage. The specific color
and the voltage depend on the chemical structure of the transparent
electrochromic polyimide. As shown in FIG. 1, the transparent
electrochromic polyimide solution is wet coated on a transparent
conductive layer 1. The solvent of the coating is removed by baking
to form the transparent electrochromic polyimide film 3.
Subsequently, an electrolyte is formed on the transparent
electrochromic polyimide film 3 by the similar wet coating to
complete a layered device. A transparent conductive layer 7 is then
attached to the layered device, and a sealing-glue 9 such as epoxy
resin is coated on the attaching portion of the two transparent
conductive layers 1 and 7. A conductive material 11 such copper
serving as a working electrode is attached thereto to complete an
electrochromic device 100.
[0020] Below, exemplary embodiments will be described in detail
with reference to accompanying drawings so as to be easily realized
by a person having ordinary knowledge in the art. The inventive
concept may be embodied in various forms without being limited to
the exemplary embodiments set forth herein. Descriptions of
well-known parts are omitted for clarity, and like reference
numerals refer to like elements throughout.
EXAMPLES
Preparation Example 1
[0021] 61.58 g (0.5 mole) of 4-methoxyaniline, 167.1 g (1.1 mole)
of cesium fluoride, and 141.1 g (1.0 mole) of p-fluoronitrobenzene
(1.0 mole) were weighted and put into a 2 L reaction tank. 0.6 L of
DMSO was then added into the reaction tank. The mixture in the
reaction tank was heated to 120.degree. C. and reacted at
120.degree. C. for 8 hours under nitrogen, and then cooled to room
temperature. The cooled reaction was poured into ethanol to
precipitate a solid, and then filtered to collect the solid. The
solid was washed by ethanol and then dried to obtain a dinitro
product. 54.8 g (0.15 mole) of the dinitro product, 680 mL of
ethanol, and 0.5 g of 10% active carbon palladium (Pd/C) were put
into a 2 L reaction tank under nitrogen. The mixture was heated to
reflux for 4 hours, and 60 mL of hydrazine was gradually added into
the reaction tank to chemically reduce the dinitro product. The
refluxed reaction was immediately filtered to remove the active
carbon palladium, and the filtration was cooled to obtain a white
diamine crystal. The white diamine crystal was collected by
filtering and then dried for following Examples and Comparative
Examples. The reaction is shown in Formula 11, and the spectra data
of the diamine product is shown as follows. IR (KBr): 3454, 3339
cm.sup.-1 (N--H stretch). .sup.1H NMR (DMSO-d.sub.6, ppm): 3.65 (s,
3H, OCH.sub.3), 4.82 (s, 4H, NH.sub.2), 6.48 (d, 2H), 6.68 (d, 2H),
6.69-6.73 (m, 4H). .sup.13C NMR (DMSO-d.sub.6, d, ppm): 55.4
(OCH.sub.3), 114.5, 115.0, 121.2, 125.8, 137.7, 143.2, 144.5,
153.0.
##STR00014##
Example 1
[0022] 5.77 g of 4-methoxytriphenylamine-based diamine (the product
in Formula 11) and 4.24 g of hydrogenated pyromellitic dianhydride
were mixed in a reaction flask. 23.3 g of NMP serving as a solvent
was added into the reaction flask, and 0.2 g of iso-quinoline
serving as a catalyst was then added into the reaction flask. The
mixture in the reaction flask was heated to 210.degree. C. for 4
hours to obtain a yellow viscous solution. The reaction is shown in
Formula 12, wherein n is 50 to 300. The spectra data of dried thin
film derived from the yellow viscous solution is shown as follows.
IR (film, cm.sup.-1): 2935, 2935, 1774, 1709. .sup.1H-NMR
(DMSO-d.sub.6, .delta., ppm): 2.14 (4H), 3.11 (4H), 3.73 (3H), 6.97
(2H), 7.03 (4H), 7.10 (2H), 7.17 (4H). .sup.13C-NMR (DMSO-d.sub.6,
.delta., ppm): 36.8, 55.4, 68.4, 115.4, 122.0, 126.0, 128.2, 139.1,
147.2, 156.8, 178.4. GPC data: M.sub.w=168,469,
M.sub.n=131,026.
##STR00015##
Example 2
[0023] 4.28 g of 4-methoxytriphenylamine-based diamine (the product
in Formula 11), 2.46 g of 2,2'-bis[4-(4-aminophenoxy)phenyl]propane
(BAPP), and 4.96 g of
bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride were
mixed in a reaction flask. 27.3 g of NMP serving as a solvent was
added into the reaction flask, and 0.2 g of iso-quinoline serving
as a catalyst was then added into the reaction flask. The mixture
in the reaction flask was heated to 210.degree. C. for 4 hours to
obtain a yellow viscous solution. The reaction is shown in Formula
13, wherein m is 35 to 140, n is 50 to 300, and m and n have a
ratio of 7:3. It should be understood that the product in Formula
13 is a random copolymer other than a block copolymer. The spectra
data of the dried thin film derived from yellow viscous solution is
shown as follows. IR (film, cm.sup.-1): 2964, 2837, 1772, 1712.
.sup.1H-NMR (DMSO-d.sub.6, .delta., ppm): 1.94, 3.36, 3.51, 3.72,
6.24, 6.93-7.01, 7.12, 7.24. .sup.13C-NMR (DMSO-d.sub.6, .delta.,
ppm): 34.0, 41.8, 55.3, 63.3, 65.6, 68.3, 69.2, 69.9, 115.4, 118.5,
122.0, 125.7, 127.0, 127.8, 128.1, 128.2, 128.6, 131.0, 139.1,
145.8, 147.2, 153.9, 156.8, 176.8. GPC data: M.sub.w=129,234,
M.sub.n=119,499
##STR00016##
Comparative Example 1
[0024] 4.07 g of 4-methoxytriphenylamine-based diamine (the product
in Formula 11) and 4.24 g of 4,4'-(hexafluoroisopropylidene)
diphthalic anhydride (6FDA) were mixed in a reaction flask. 23.3 g
of NMP serving as a solvent was added into the reaction flask, and
0.2 g of iso-quinoline serving as a catalyst was then added into
the reaction flask. The mixture in the reaction flask was heated to
210.degree. C. for 4 hours to obtain an orange red viscous
solution. The reaction is shown in Formula 14, wherein n is 50 to
215. It should be understood that the product in Formula 14 is a
random copolymer other than a block copolymer. The spectra data of
the dried thin film derived from orange red viscous solution is
shown as follows. IR (film, cm.sup.-1): 1786, 1722. .sup.1H-NMR
(DMSO-d.sub.6, .delta., ppm): 3.74, 6.98, 7.09, 7.16, 7.31, 7.74,
7.93, 8.14.
##STR00017##
Comparative Example 2
[0025] 2.917 g (9.55 mmole) of 4-methoxytriphenylamine-based
diamine (the product in Formula 11) and 2.083 g of pyromellitic
dianhydride (9.55 mmole) were mixed in a reaction flask. 11.67 g of
NMP serving as a solvent was added into the reaction flask, and
0.05 g of iso-quinoline serving as a catalyst was then added into
the reaction flask. The mixture in the reaction flask was heated to
210.degree. C. and reacted at 210.degree. C. for 0.5 hours to
precipitate a brown cake. Even more solvent could not dissolve the
brown cake. In short, the solubility of the brown cake is too low
to form a film. The reaction is shown in Formula 15.
##STR00018##
Comparative Example 3
[0026] 2.8025 g (0.014 mole) of 4,4'-oxydianiline, 2.4631 g (0.006
mole) of BAPP, and 4.9636 g (0.02 mole) of
bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride were
mixed in a reaction flask. 23.87 g of NMP serving as a solvent was
added into the reaction flask, and 0.2 g of iso-quinoline serving
as a catalyst was then added into the reaction flask. The mixture
in the reaction flask was heated to 210.degree. C. and reacted at
210.degree. C. for 4 hours to obtain a yellow viscous solution. The
reaction is shown in Formula 16, wherein m is 35 to 140, n is 15 to
60, and m and n has a ratio of 7:3. It should be understood that
the product in Formula 16 is a random copolymer other than a block
copolymer. The spectra data of the yellow viscous solution is shown
as follows. IR (film, cm.sup.-1): 2963, 2838, 1773, 1714.
.sup.1H-NMR (DMSO-d.sub.6, .delta., ppm): 1.63, 3.41-3.59, 6.29,
6.96, 7.06, 7.12-7.14, 7.18, 7.26.
##STR00019##
Comparative Example 4
[0027] 7.7373 g (0.021 mole) of
4,4'-(1,1'-biphenyl-4,4'-diyldioxy)dianiline, 3.6946 g (0.009 mole)
of BAPP, and 7.4457 g (0.03 mole) of
bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride were
mixed in a reaction flask. 44.04 g of NMP serving as a solvent was
added into the reaction flask, and 0.28 g of iso-quinoline serving
as a catalyst was then added into the reaction flask. The mixture
in the reaction flask was heated to 210.degree. C. and reacted at
210.degree. C. for 4 hours to obtain a yellow viscous solution. The
reaction is shown in Formula 17, wherein m is 42 to 175, n is 18 to
75, and m and n has a ratio of 7:3. It should be understood that
the product in Formula 17 is a random copolymer other than a block
copolymer. The spectra data of the yellow viscous solution is shown
as follows. IR (film, cm.sup.-1): 2963, 2837, 1772, 1714.
.sup.1H-NMR (DMSO-d.sub.6, .delta., ppm): 1.63, 3.43-3.53,
6.29-6.30, 6.96, 7.05, 7.13, 7.18, 7.25, 7.68.
##STR00020##
Example 3
[0028] The polyimides prepared in Examples 1 to 2 and Comparative
Examples 1 to 4 were dissolved in dimethylacetamide (DMAc) and
diluted by DMAc to an appropriate concentration, respectively. The
polyimide solution was coated on a glass substrate by blade coating
to form a film with a thickness of 15 .mu.m. The film was baked at
a temperature of 50.degree. C. for 0.5 hour, and then baked at a
temperature of 140.degree. C. for 15 minutes to obtain a polyimide
film. As shown in appearance, The polyimide films of Examples 1 to
2 and Comparative Examples 3 to 4 were transparent (colorless), and
the polyimide film of Comparative Example 1 was opaque yellow. In
Comparative Example 2, polyimide was brown cake not dissolved in
DMAc, and low molecular weigh imide oligomer dissolved in DMAc.
[0029] The electrochemical properties of the polyimide films were
then measured to monitor colors of the polyimide films under
different voltages. The DMAc solution of the polyimide or copolymer
thereof was coated on an ITO glass to serve as a working electrode.
0.1 M acetonitrile (CH.sub.3CN) solution of TBAP served as an
electrolyte, and ferrocene (Fc) served as a standard. The polyimide
films of Examples 1 or 2 were applied a voltage from 0V to 1.25 V,
such that the appearance of the polyimide films was transferred
from transparent (colorless) to deep blue. The polyimide film of
Comparative Example 1 was applied a voltage from 0V to 1.25 V, such
that the appearance of the polyimide film was transferred from
opaque yellow to blue. The polyimide film of Comparative Examples 3
or 4 were applied a voltage from 0V to 1.25 V, but the appearance
of the polyimide films remained transparent (colorless) (no
electrochromicity). The low molecular weigh imide oligomer
(dissolved in DMAc) film of Comparative Example 2 was applied a
voltage from 0V to 1.25 V, such that the appearance of the imide
oligomer film was transferred from opaque brown to blue.
[0030] The physical properties of the polyimides in Examples 1 to 2
and Comparative Example 1 to 4 are tabulated in Table 1.
TABLE-US-00001 TABLE 1 Solubility in Appearance Film-forming
organic before applying Electro- ability solvent voltage chromism
Example 1 Yes Soluble Transparent Yes Example 2 Yes Soluble
Transparent Yes Comparative Yes Soluble Opaque deep Yes Example 1
yellow Comparative No, Insoluble Brown cake Yes Example 2
precipitated without film during forming ability polymerization
Comparative Yes Soluble Transparent No Example 3 Comparative Yes
Soluble Transparent No Example 4
[0031] As described, if the diamine for forming the polyimide dose
not contain the diamino triphenylamine, the polyimide will lose
electrochromicity. On the other hand, if the dianhydride for
forming the polyimide is the aromatic dianhydride other than the
cycloaliphatic dianhydride, the polyimide will not be transparent
without being electrified.
Example 4
[0032] ITO layer with a thickness of 0.7 mm was sputtered on a 12
inch glass layer to complete a transparent conductive layer (ITO
glass). Subsequently, 12.5 g of PMMA, 2.5 g of LiClO.sub.4, 38.85 g
of acetonitrile, 15.0 g of ethylene carbonate (EC), and 15.0 g of
propylene carbonate (PC) were mixed and slowly heated to 50.degree.
C. to form a electrolyte gel. 12 inch of polyimide (the product in
Formula 12) film was coated on the conductive surface of the ITO
glass, and then baked to remove the solvent thereof. The
electrolyte gel was coated on the transparent electrochromic film,
and then attached to another ITO glass. Thereafter, the attaching
portions of the two transparent conductive layers were coated by
sealing epoxy resin to complete a simple electrochromic device. A
voltage of 2.4 V was applied to the polyimide film through an
external line and the ITO layer, such that the appearance of the
electrochromic device was transferred from transparent (colorless)
to deep blue.
[0033] It will be apparent to those skilled in the art that various
modifications and variations can be made to the disclosed methods
and materials. It is intended that the specification and examples
be considered as exemplary only, with the true scope of the
disclosure being indicated by the following claims and their
equivalents.
* * * * *